In recent years, an automotive navigation device is used to display a current position of a subject vehicle at a corresponding position on a map. The navigation device also determines whether the subject vehicle is traveling on a road based on a comparison between the current position of the subject vehicle and the corresponding position on the map (refer to a Japanese Patent Document JP-A-2003-130651).
The navigation device uses map data that is derived from data collection procedure such as an aerial photo, a survey of a site or the like. Therefore, the map data does not always reflect a current condition of a road. That is, for example, a road constructed after the map data collection does not appear on the map. Thus, the current position of the subject vehicle goes out of a road on the map shown in the navigation device when the subject vehicle travels on a newly constructed road that is not drawn on the map.
A user of the navigation device recognizes that the subject vehicle travels on the newly constructed road when the current position of the vehicle goes out of the road on the map. In this case, the user can obtain an updated map data at a cost and trouble on the user's side. That is, usability of the map decreases when the subject vehicle travels on the newly constructed road without having the updated map data, because the current position of the subject vehicle displayed on the map travels outside of the road.